Chalcidoidea are a megadiverse group of minute insects containing an estimated 500,000 species worldwide. Most target species are less than 2 mm. long! Researchers at the University of California, Riverside, and Texas A&M University will focus on training new researchers in both morphological and molecular methods for recognition of new species, and understanding phylogenetic relationships, through a series of worldwide monographic studies of five groups of related wasps. The research will emphasize novel electronic tools and resources for manipulation, sharing, and storage of taxonomic and host data, and development of new methods for electronic communication between collaborating laboratories worldwide.
Chalcidoidea are one of the most important groups for the natural or directed control of arthropod pest populations. Many of the target taxa are effective natural enemies of insect pests and they are widely used in agriculture and forestry for their control. Effective use of parasitoids in natural or manipulative biological control depends on a mature and sophisticated species-level taxonomy. Chalcidoidea also form a substantial, important, and under-appreciated component of terrestrial ecosystems. The electronic and monographic products of this research will be of great benefit to systematists, agricultural scientists, and all those that wish to understand and conserve terrestrial biodiversity.
Just over 23,000 species of Chalcidoidea have been described, but conservative estimates place the global diversity at around 500,000 species. Systematists have faced a myriad of challenges when studying Chalcidoidea, mostly stemming from their very small size (many less than 5-mm total body length), morphological complexity, and lack of a robust hypothesis of relationships among chalcidoid groups. Because of their ability to parasitize and kill other insects, they have tremendous importance in both natural and agricultural ecosystems as biological control agents. In a group so massive, it is important to address this taxonomic impediment by training new researchers. Overall, we provided training for three postdoctoral researchers, nine graduate students and 19 undergraduates. Research focused on three of the most important families for natural and biological control of insect pests: Aphelinidae, Signiphoridae and Trichogrammatidae, and also on other families, including the ant-parasitic Eucharitidae. All of the families include species that are economically important through their control of pest insects in field crops, tree crops and forests. To use these insects efficiently, we need better means to identify them using both visual and molecular tools, and a better understanding of their relationships to allow for better prediction of their host associations, natural range, reproductive behavior, and potential to impact a targeted pest species. As an example, a parasitic wasp species, Cales noacki, was imported to California in the 1970s as a biological control agent of wooly whitefly, a serious pest of citrus at the time. Using molecular methods, we discovered a new cryptic species in California attacking the same host on the same citrus trees. We were able to use wing morphology to utilize all of the slide-mounted, vouchered museum material from the original importations in the 1970s, and we then proposed a historical scenario of importation of multiple species as part of the original biological control program in Chile and Argentina. Further, we discovered a massive cryptic species complex across South America that may allow researchers to evaluate new potential biological control agents or better evaluate what is being released into new areas. From one recognized species we have now discovered more than 20 distinct species across South America that are morphological nearly identical. The distinctive family Signiphoridae contains species that are primary parasites of pest insects such as scales, mealybugs and whitefly, but other, closely related species are hyperparasites, that is parasites of parasites. Therefore, to understand the roles of these species in agricultural systems absolutely requires that we understand the species taxonomy, and that robust, easy-to-use tools are available for their identification. As in Cales and many other genera of parasitic Hymenoptera, many new and cryptic species were discovered in Signiphoridae using both molecular and advanced morphological tools, many of which differ in important biological characteristics such as host relationships. To date the project has discovered at least 31 new species of Signiphora, 8 new species of Thysanus, and one new species of Clytina. Emphasis has also been placed on development of user-friendly, well-illustrated, electronic identification devices that will be publicly available on-line. Along with our taxonomic monographs and phylogenetic results, we developed new digital imaging techniques and new systems for managing images and tracking voucher and museum specimens, and we participated in developing an online data management system that is being used by taxonomic research groups worldwide. All of these tools facilitate the publication of species descriptions and contemporary, electronic taxonomic monographs, and provide convenient and easy-to-use portals for this information to be made available on-line to scientists, agriculturalists and the public. Over the course of this project, we produced the first phylogenetic hypothesis for the superfamily and made available revisionary treatments of economically important Aphelinidae, Eucharitidae, Eulophidae, Signiphoridae and Trichogrammatidae. These are small steps to understanding the entire group, but we have developed the necessary tools to greatly expedite both the pace and quality of this work in the future.
